Thermostatic switch



Aug. 23, 1927. 1,639,888

, w. J. HAWKINS THERMOSTATIC SWITCH Original Filed Dec. 12, l9 l 9 INVENTOR [Vi/ford] amf/ias IBYKW M ATTORNEY Patented Aug. 23, 1927.

UNITED STATES PATENT OFFICE.

WILFOBID J'. HAWKINS, 01 MONTCLAIB, NEW JERSEY.

TEEBKOBTATIC SWITCH.

Application filed December 12, 1919, Serial 110. 344,385. Renewed. January 27, 1927.

This invention relates to switches of the type which are .actuated automatically upon the occurrence of certain changes n temperature, such switches being particularly useful for the controlling of refrigerating machinery and the like.

The objects of the invention are to provide a simple, reliable, practical and efficient switch of this character which will operate to make and break the circuit with a quick, positive action and which will be relatively small and compact as to structure.

A further object which may be mentioned here is to provide for the ready adjustment of the mechanism to produce operation of the same at difi'erent predetermined temperatures.

Various other objects and the novel features of construction, combination and arrangement of parts which go to make up the invention will all appear as the specification proceeds and which is to be read in conjunction with the accompanying drawing wherein I have illustrated the invention embodied in one of its most simple commercial forms.

In the drawing referred to Figure 1 is .a vertical sectional view of one of the switches.

Figure 2 is a bottom plan view of the same.

In the following description like reference characters apply to like parts in both the views.

The switch mechanism is actuated, in the present disclosure, in accordance with the expansion and contraction of a fluid, such as sulphur dioxid, which is highly sensitive to temperature changes and which has a relatively high coefficient of expansion. This fluid is contained within a' suitable vessel 5 which may be constructed with a filling opening 6. This vessel or container is provided with a spring wall 7, bowed as indi cated in Figure 1 and thus tensioned so that it will buckle to opposite sides of a common plane. This wall thus operates as a buckling spring disc and said wall is also utilized in the present disclosure as one of the terminals of the circuit which. is to be controlled. lhe other terminal consists of a sliding plunger 8 having a contact head 9 bearing on the buckling spring top of the container when in its upwardly buckled condition, said plunger being slidingly guided in abushing 10 which is supported by insulation 11 in the central arched portion 12 of a bracket which is provided with downwardly projecting arms 13 extended beneath the container. 'l'llese lower arms of the bracket serve as supports for the container and may be provided with mechanism, such as the screws 14 illus trated, for adjusting the container vertically. In such vertical movements the container may be guided over the supporting arms 13 by the brackets 15 which have, as shown, dependent arms slidingly engaged over the opposite edges of the supports 13.

The contact plunger is shown as yieldingly held engaged with the buckling spring member by a helical spring 16. This serves to insure a positive engagement with the buckling spring and hence good electrical conductivity at this point.

The buckling spring top of the container is shown in the drawing as subjected to additional pressure by means of a helical spring 17 hearing on the same and seated at its lower end in an annular groove 18 formed therein, said spring having a bearing at its upper end in an annulus 19 engaged with the overstanding portion of the bracket or supporting yoke. This annular groove in the buckling spring disc not only serves as a seat to position the lower end of the return spring 17 but also gives resilienc to the disc and materially assists in the uckling action thereof. 4

The buckling spring top of the container is included in circuit in the present disclosure by means of a conductor 20 brought to a binding screw 21 on the yoke, said yoke being in electrical contact with the container and hence electrically connected with the buckling top of said container. The contact plunger is included in circuit by a conductor 22 which is brought to a binding nut 23 engaged on the bushing in which the plunger is guided.

\Vhen the parts are in the position indicated in full lines in Figure 1, it will be apparent that the circuit will be completed through the plunger and the buckling spring member. This may be the condition when the temperature sensitive fluid within the container has expanded, due to a rise in temperature. In buckling the spring in this directiomthe expanding fluid overcomes the pressure of the spring 17. On contraction of the fluid the spring 17 will exert its pressure to buckle the spring in the reverse direction. Under these circumstances, the contact plunger attempts to follow the buckling disc, but is arrested in the course of such movement by the enga ement of the stop 24 thereon with the end 0 the bushing 10. The stop 24 may be in the form of a nut adjustably threaded on the upper end of the plunger so that the lunger may be brought to rest at any pre etermined point in its movement. Preferably the movement of the plunger will be stopped when the contact head thereof is in about the position indicated in dotted lines in Figure 1, that is, approximately on or above the central plane .of the buckling movement. This arresting the movement of the plunger produces a quick break of the circuit because at the moment the plunger is brought to rest, the

' spring is traveling at high speed and snaps quickly away therefrom. In the movement of the buckling spring in the reverse direction, the spring snaps quickly into contact with the plunger head at about the time the spring is moving past the center of its movement and thereafter carries the plunger along with it. It will be seen that both the acts of making and breaking the circuit are positive and quick.-

The bodily adjustment of the container can be utilized to adjust the pressure of the return spring 17 and after this adjustment has been made the plunger stop may be adjusted to produce the proper plunger movement at such spring adjustment. Conversely, in some instances the plunger adjustment may be made first and thereafter 'housed within a dome or the container be bodily adjusted to suit the plunger movement The switch as a whole may ordinarily be cover, such as that indicated at 25. It is indicated as secured in this 'coveringzin the present illustration by means of screws 26 passed through the cover into blocks of insulating material 27 l also that w ile I which are shown as secured to the sides of the supporting yoke byscrews 28. It will be apparent that with this construction the swltch is entirely insulatedfrom the cover and may at any. time be removed therefrom as a unit b simply taking out the screws 26.-

It will e apparent from the foregoing that the device of my invention'can be produced quite inex ensively and can be made in very com act' fbrm. It will be understood have disclosed a practical and, at the present time, a preferred embodiment of the invention, varlous modifications and changes may be made without departure from the true spirit and scope of the invention as defined in the appended claims.

What I claim is:

1. A thermostatic switch comprising a container provided with a spring tensioned wall arranged to buckle in opposite directions, 2. support for said container having upper and lower arms, switch mechanismmounted on the upper arm of said support and provided with an actuating member disposed in position to be engaged by the buckling wall and means carried by the lower arms of the support for effectin relative adjustment of the buckling wal and switch actuating member on the support.

2. A thermostatic switch comprising a container for an expansible fluid provided with a top tensioned to buckle in opposite directions, a yoke having an arched portion extending over the buckling top and supporting arms extending beneath the container, electric switch mechanism mounted on the arched portion of the yoke provided with a plunger engageable with the buckling top, a spring interposed between the arched portion of the yoke and the buckling top of the container and means carried by the supporting arms of the yoke for adjusting said container against the tension of said spring.

In combination, a spring arranged to be buckled in opposite directions and switch mechanism comprising a contact controlling member movable in a plane substantially corresponding to the plane of buckling movement, said contact controlling member having a bearing on the spring when said spring is buckled toward the same, a stop for arresting the movement of said contact controlling member when the sprin is buckled in the reverse direction and a single supporting member adapted to support said contact controlling member and to cooperate with said stop.

4.111 combination, a spring arranged to buckle in opposite directions, a contact controlling member engaged by movable in substantially buckling movement of the said sprin and the plane 0 the spring, a stop for holding said contact controlling member out member adapted to support said contact controlling member and to cooperate with 'saidjstop.

5. In combination, a spring arranged to buckle in opposite directions, a contact controlling member engaged by said spring and movabe in substantially the plane of the buckling movement of the spring, a stop for holding said contact controlling member out of engagement with the spring when said spring is buckled away from said contact controlling member, means for relatively adjusting the spring'and contact controlling member and a single supporting member adapted to support said contact. controlling member and to cooperate with said stop.

6. A thermostatic switch comprising a container for an expansible fluid provided with a wall tensioned to buckle in opposite directions, a plunger operable in the plane of such bucklin movement and engaged by the buckling wa 1 when the same is buckled toward said plun er, a stop for arresting the movement of t e plunger and for holding the same out of contact with the wall when buckled in" the reverse direction and a single supporting member adapted to support said plunger and to cooperate with said stop.

7. A thermostatic switch comprising a container for an expansible fluid provided with a wall tensioned to buckle in opposite directions, a plunger operable in the plane of such buckling movement and engaged by the buckling wall when the same is buckled toward said plunger, a stop for arresting the movement of the plunger and for holding the same out of contact with the wall when buckled in the reverse direction, and a single supporting member adapted to support said plunger and to cooperate with said stop and a circuit having said plunger and buckling wall as its terminals.

8. A thermostatic switch comprising a container for anexpansible fluid provided with a wall tensioned to buckle in opposite directions, a plunger operable in the plane of such buckling movement and engaged by the buckling wall when the same is buckled toward said plunger, a stop for arresting the movement of the plunger and for holding the same out of contact with the wall when buckled in the reverse direction, and a single supporting member adapted to support said plunger and to cooperate with said stop and a spring for thrusting the plunger toward the buckling wall.

9. A thermostatic switch comprising a container for an expansible fluid and having a spring top tensioned to buckle in reverse directions, said top having an annular groove therein, a helical spring bearing on the buckling top and seated at one end in said annular groove, a support for the opposite end of said spring, a plunger insulated from said support and movable in the plane of buckling movement, a spring for thrusting the plunger toward said buckling wall, a stop for preventing the plunger from following the buckling wall to the extreme of its movement and a single supporting member adapted to support said plunger and to cooperate with said stop and an electric circuit having the plunger and the buckling wall as its terminals.

10. In a switch of the character described,

a reversely buckling spring, switch mechanism for engagement therewith and movable in the direction of the buckling of the spring, adjustable stop mechanism for arresting the movement of said switch mechanism when the spring is buckled in one direction, and a single supporting member adapted to support said switch mechanism and to cooperate with said stop mechanism and means for effecting relative bodily adjustment of said member with respect to the buckling spring.

11. In a switch of the character described, a buckling spring movable to opposite sides of an intermediate plane, a movable switch element at one side of said plane, means for causing said switch element to follow the buckling spring as the same is buckled to the opposite side of said plane, means for arresting the movement of said element substantiaily at said plane and a single supporting member adapted to support said switch ele ment and to cooperate with said arresting means.

12. In a switch of the character described, a spring arranged to buckle to opposite sides of a substantially horizontal center, a movable switch element above said spring and arranged to follow the downward movement of the spring, means for arresting the downward movement of said switch element at a point above the center of the buckling movement to thereby position said element to be engaged by the spring as the same is buckled past the center on its return movement and a single supporting member adapted to support said switch element and to cooperate with said arresting means.

13. In a switch of the character described, a buckling spring disc having an annular groove in the buckling portion thereof, a spring seated in said groove for buckling the spring disc in one direction, means for buckling the spring disc in the reverse direction and switch contacts controlled by the spring disc.

14. In a thermostatic switch, a closed container for an expansible fluid having a spring wall arranged to be buckled outwardly by expansion of the fluid and to be buckled inwardly upon contraction of said fluid, a movable switch element positioned to be actuated by said reversely buckling wall and a single supporting member adapted to support said switch element and to limit the extent of movement of said switch element.

15. In a thermostatic switch, a closed container for an expansible fluid having a spring wall arranged to be buckled outwardly by expansion of the fluid and to be buckled inwardly upon contraction of said fluid, a movable switch element positioned to be engaged and shifted by said wall in its outwardly buckling movement, stop mechanism for arresting te movement of said switch element on the inwardly buckling movement of the wall and a single supporting member adapted to support said switch element and to cooperate with said stop mechanism.

In witness whereof, I hereunto set my hand this 9th day of December, 1919.

W'ILFORD J. HAWKINS. 

